The electromyographic activity of the soleus muscle is a reliable indicator of its functional status. Support unloading causes an immediate cessation of electrical activity of the soleus muscle, which resumes upon restoration of the support load. Prolonged support unloading, however, results in the emergence of spontaneous electrical activity of the soleus muscle. Previous research has established a correlation between this activity and the presence of the potassium-chloride cotransporter (KCC2) on the membranes of spinal cord motor neurons. It has also been demonstrated that the administration of the KCC2 activator prochlorperazine can eliminate spontaneous soleus muscle activity. Here, we aimed to investigate the effect of CLP290, an alternative KCC2 activator, on the spontaneous tonic activity of the rat soleus muscle. The results indicated that daily administration of CLP290 to rats during a 14-day period of hindlimb suspension prevented the reduction in KCC2 levels in lumbar spinal cord motor neurons and the increase in soleus muscle spontaneous tonic activity. Notably, there were no significant differences in the cross-sectional area of slow-type fibers between the antiorthostatic suspension groups with and without CLP290 administration.

The electromyographic activity of the soleus muscle is a reliable indicator of its functional status. Unloading of support causes an immediate cessation of electrical activity in the soleus muscle, which resumes upon restoration of the support load. Prolonged support unloading, however, results in the emergence of spontaneous electrical activity in the soleus muscle. Previous research has established a correlation between this activity and the presence of the potassium-chloride cotransporter (KCC2) on the membranes of spinal cord motor neurons. Additionally, it has been demonstrated that the introduction of the KCC2 activator prochlorperazine can eliminate spontaneous muscle activity. This study aimed to investigate the impact of CLP290, an alternative KCC2 activator, on the spontaneous tonic activity of the rat soleus muscle. The results indicated that daily administration of CLP290 to rats during a 14-day period of hindlimb suspension prevented the reduction in KCC2 levels in the motor neurons of the lumbar spinal cord and the increase in spontaneous tonic activity in the soleus muscle. Notably, there were no significant differences in the cross-sectional area of slow-type fibers between the antiorthostatic suspension groups with and without CLP290 administration.

The soleus is one of the key muscles for stability of the majority mammals in Earth's gravity. It is well known that as soon as a laboratory animal (rat) is put in a real or modeled weightlessness (loss of the hindlimb contact with substrate due to tail-suspension) the electrical activity in m. soleus decreases sharply. However, starting on day 3 of the functional unloading this activity renews and grows to the level characteristic of control animals (approximately by day 14 of suspension). The phenomenon was termed "the spontaneous activity of unloaded postural muscle". The review discusses spinal mechanisms of the spontaneous postural muscle activity, the input of ion co-transporters in marrow motoneurons specifically, and effect of this activity on intra-cell signaling in fibers of unloaded m. soleus.

It is well known that the inactivity of mammalian skeletal muscles leads to the cessation of their electrical activity and is accompanied by atrophic changes in muscle fibers. However, it has been repeatedly noted that starting from the 3rd day of functional unloading, spontaneous rhythmic neuromuscular activity appears, which is the result of a decrease in the expression of the potassium chloride co-transporter KCC-2 in neurons of the lumbar spinal cord. A decrease in the expression of KCC-2 and the onset of autonomous electrical activity of the unloaded muscle can be prevented by the administration of the neuroleptic prochlorperazine. Thus, the aim of this study was to evaluate the structural and signaling effects of the reduced spontaneous activity of the unloaded m.soleus. It was found that daily administration of prochlorperazine to rats under conditions of 7-day simulated gravitational unloading prevented a decrease in the content of the main markers of ribosome biogenesis (c-Myc, 18S rRNA and 28S rRNA), and also partially prevented a decrease in the cross-sectional area of fast and slow muscle fibers in the m.soleus. Morphofunctional changes caused by a decrease of spontaneous activity of the unloaded muscle were accompanied by complete or partial prevention of activation of key proteolytic markers expression (MuRF-1, MAFbx/atrogin-1, ubiquitin). Thus, we assume that spontaneous neuromuscular activity may be a factor that augments muscle atrophy during the first week of functional unloading.

The mechanoelectrical feedback in the heart is based on the work of mechanically gated (MGCs) and mechanosensitive (MSCs) channels. Since microgravity alters the heart’s morphological and physiological properties, we hypothesized that the expression of both MGCs and MSCs would be affected. We employed RNA transcriptome sequencing to investigate changes in the gene transcript levels of MGCs and MSCs in isolated rat ventricular cardiomyocytes under control conditions and in a simulated microgravity environment. For the first time, our findings demonstrated that simulated microgravity induces alterations in the gene transcript levels of specific MGCs, such as TRPM7, TRPV2, TRPP1, TRPP2, Piezo1, TMEM63A, TMEM36B, and known MSCs, including K 2P 2.1, K 2P 3.1, Kir6.1, Kir6.2, Na V 1.5, Ca V 1.2, K V 7.1. However, other voltage-gated channels and channels lacking a voltage sensor remained unaffected. These findings suggest that the altered expression of MGCs and MSCs could lead to changes in the net currents across the membrane, ultimately impacting the heart’s function.

It is known that mTORC1-dependent pathway is involved in the activation of muscle protein synthesis and hypertrophy in response to mechanical stress. However, mechanosensors that mediate sensing and transmission of mechanical signals to the mTORC1 signaling pathway (mechanotransduction) are not yet identified. Mechanically activated (MA) ion channels are viewed as potential candidates for the role of such sarcolemmal mechanosensors. The aim of our work was to investigate the potential role of MA channels (Piezo1) in the activation of the mTORC1 pathway in the isolated rat soleus muscle in response to mechanical stress. Wistar rats were divided into 3 groups: 1) "Control" (isolated muscles were not exposed to MA channel inhibitor or Piezo1 channel activator); 2) "Gadolinium" (muscles were incubated with MA channel inhibitor, gadolinium chloride); 3) "Yoda" (muscles were incubated with Yoda1, Piezo1 activator). In rats from each group, the soleus from the left limb was incubated in the appropriate solution without mechanical stress in the form of a passive stretching, and the soleus from the right limb was subjected to passive stretching and then incubated in the appropriate solution. Phosphorylation of mTORC1 targets (p70S6K, rpS6, 4E-BP1) in rat soleus was determined by PAGE and immunoblotting. After passive stretching of the isolated soleus muscle there was an increase in phosphorylation of p70S6K, its substrate, rpS6, as well as 4E-BP1, by 38.5%, 168%, and 112%, respectively, compared to the soleus muscle that was not subjected to stretching. Incubation of the muscles with gadolinium completely prevented the activation of mTORC1 markers caused by stretching. Incubation of the soleus muscle in the solution with Yoda1 resulted in a decrease in the mechano-dependent phosphorylation of p70S6K, rpS6, and 4E-BP1 compared to a muscle that was not exposed to Yoda1. Thus, Piezo1 channels do not appear to play a role in the activation of mTORC1 signaling in rat soleus muscle in response to passive stretching.

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The nonequilibrium luminescence of a C 2 molecule in a jet of products of the high-temperature erosion of a diaphragm discharge in vacuum ( P init = 10 Pa) at an early stage of afterglow (0.8–1.2 ms) is studied using the emission spectra of the C 2 Swan bands system ( d 3 П g – a 3 П u ) by comparing the radiation intensities in the bands forming sequences with ∆ν = +1 and 0. The experimental results at the stage of the end of condensation of discharge products are obtained. The processes of obtaining a variety of highly dispersed structures are considered and their parameters are evaluated.

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A mathematical model describing the mutual influence of bad-defined various human characteristics is constructed. This model is described by a system of differential equations that reflect the “rate” of change in a characteristic as a function of the frequency of interaction with other characteristics. The transition from differential equations to equations in finite differences and the introduction of the von Neumann neighborhood on the resulting square space of the frequency of interaction of various human characteristics allows us to introduce a cellular automaton. The sequential execution of iterations in the cellular automaton allows to track how each of the entered characteristics depends on the behavior of other characteristics.

The mechanism of moving an atom through a crystal lattice without vacancies is considered. This situation can be observed when all sites of the lattice are occupied by atoms of the same type, or when some of them are occupied by isotopes of the same atoms. It is shown that in a three-dimensional crystal lattice constructed from identical atoms without vacancies, one-dimensional motion of the own atom along the lattice chain is possible. This movement is realized as a Frenkel-Kontorova soliton.

Abstract The effect of the terrestrial gravitation field on crystal growth from a solution–melt during spontaneous crystallization is considered, taking into account that the space station (SS) and a laboratory at the Earth, in which the crystallization processes occur, are a noninertial system. It is shown that the specific feature that distinguishes the crystal growth in the terrestrial conditions is the pressure in the melt caused by the supporting force (the Newton third law). This pressure is absent at SS, and this fact leads to an increase in the unit cell of the melt that undergoes the first-order phase transition. As a result, the crystals grown at the SS have larger sizes than the same crystals grown in terrestrial conditions. They also exhibit an excess stress, the value of which is equal to the support pressure, which is absent at the SS. This situation is compared to the experimental data on growing CrSi_2 crystals from a solution–melt in Zn of the Cr–Si–Zn system.

The effect of the terrestrial gravitation field on crystal growth from a solution–melt during spontaneous crystallization is considered, taking into account that the space station (SS) and a laboratory at the Earth, in which the crystallization processes occur, are a noninertial system. It is shown that the specific feature that distinguishes the crystal growth in the terrestrial conditions is the pressure in the melt caused by the supporting force (the Newton third law). This pressure is absent at SS, and this fact leads to an increase in the unit cell of the melt that undergoes the first-order phase transition. As a result, the crystals grown at the SS have larger sizes than the same crystals grown in terrestrial conditions. They also exhibit an excess stress, the value of which is equal to the support pressure, which is absent at the SS. This situation is compared to the experimental data on growing CrSi 2 crystals from a solution–melt in Zn of the Cr–Si–Zn system.

We have analyzed crystal growth in “terrestrial” conditions and in conditions on a space station. It is shown that CrSi2 crystals grown from the Zn melt of the Cr–Si–Zn system in zero-gravity conditions exhibit an excess stress comparable with the excess pressure in the melt due to the support reaction on Earth, as well as the Laplace pressure.

It is shown that CrSi2 crystals are grown from the Zn melt of Cr-Si-Zn system in «weightlessness” conditions have excessive stress. This stress is comparable in magnitude to the excess pressure in the melt. This overpressure is caused by the reaction of the "support" on Earth to this melt, plus (with the corresponding sign) the Laplace pressure

Experimental data obtained in a study of CrSi 2 microcrystals grown under microgravity conditions from a Zn melt in the Cr–Si–Zn system by the mass crystallization method and then placed in terrestrial conditions are presented and analyzed. New properties of crystals of this kind are observed.

Experimental data and their analysis on the study of Cr〖Si〗_2 microcrystals grown in weightlessness from the melt Zn of Cr-Si-Zn system by mass crystallization and placed in earth conditions are presented. New properties of such crystals are found.

AbstractThe effect of a channel’s symmetry type on its internal dimensions, which would allow the movement of atoms (ions, molecules), has been discussed. Based on the symmetry properties of the Lagrange function for the channel and the properties of the channel itself, its internal dimensions are determined. The particular example of the crystallographic channel of quartz and its dislocations is considered.

The effect of a channel's symmetry type on its internal dimensions, which would allow the movement of atoms (ions, molecules), has been discussed. Based on the symmetry properties of the Lagrange function for the channel and the properties of the channel itself, its internal dimensions are determined. The particular example of the crystallographic channel of quartz and its dislocations is considered.

Energy of threshold breakdown of through holes in metal foils of different thicknesses by powerful laser radiation is investigated experimentally. Properties of foil matter at “liquid metalgas” phase transition are revealed. One of controlled parameters of the threshold breakdown is the outlet on the shady side of the target. The threshold breakdown hole is outlet of hole for a given foil thickness when further decrease of energy is not able to create.